For example, a reproducing apparatus accomplishes a masking process for removing the designated region of a document to be reproduced from the reproduced image and a trimming process for reproducing the designated region only.
In case a certain region is to be designated on the document for those processes, a small region such as a region of a few letters or a letter itself is usually smeared out for the designations, and a large region difficult to smear out is conveniently designated by a closed loop. These methods are frequently used.
The latter image processing method for detecting a designated region with the closed loop, as described above, is proposed in Japanese Patent Laid-Open Nos. 57 - 68371, 57 - 194668 and 57 - 194670, for example. On the other hand, the former image processing method for detecting the designated region by smearing is proposed in Japanese Patent Laid-Open No. 58 - 60876, for example.
According to the method disclosed in Japanese Patent Laid-Open No. 57 - 89371, however, the "outside region section", as defined in the present invention, is used to detect the "continuous" "designated section". Therefore, in case the regions are designated, as shown in FIG. 22, the region A can be correctly detected, but the region B cannot.
According to the above-specified technique, moreover, what can be detected either the region designated by the closed loop or the region designated to be smeared out can be detected. In other words, in a document having the regions designated by the closed loop and to be smeared out, these individual designated regions cannot be accurately detected.
This is because the designated region detecting method detects the region by processing the information of a designated point only. Let it be considered to detect the region of an image smeared out, as shown in FIG. 1A, and the region designated by a closed loop, as shown in FIG. 1B. For example, it is necessary for a scanning line Lb to detect a region section extending from a point Pa to a point Pb in the case of FIG. 1A but region sections extending from a point Pc to a point Pd and from a point Pe to a point Pf in the case of FIG. 1B. Despite this necessity, however, the information of the designated points is absolutely identical from a scanning line La to a scanning line Lc so that they cannot be discriminated. In the present invention, therefore, the "region portion (or region section)" is used for detecting the "continuous" "designated section". In addition to the information of the designated points, the information of the image points is preferably used, too, for detecting the "designated section".
Thus, even in the designation of the region shown in FIG. 22, the designated region can be correctly detected even if the designations by the closed loop and by the image smeared out coexist.